The massive quantity and dizzying variety of content about the recent Florida high school shooting on Facebook show how hard it's going to be for the company to fight fake news.
If Facebook wants to rid itself of misinformation, it's going to take more than tweaking the software it uses to select it. The social network will also need to overhaul how it displays different types of content and how it helps users find it on the site.
For starters, what you see on Facebook about the tragedy depends on what you search for.
Different searches done by CNBC on Thursday morning for "Florida high school shooting," "Florida school shooting" and "Florida shooting," for example, turned up three distinct sets of videos at the top of the resulting Facebook pages.
The sources of the videos ranged from national networks such as NBC, CBS and Fox to local news channels, individual video bloggers and foreign sources like China's Xinhua news agency.
From there the content fragments still further into at least five different types of content: videos, public posts, articles, posts from groups, and another section called "what people are saying."
That last category surfaced some posts from my Facebook friends, suggesting that content was also chosen for me based on my network.
Among the posts were some still claiming that students speaking out against the shootings were paid actors, and others refuting that cynical conspiracy theory.
Similarly, there were competing posts on another issue: Some said one shooting survivor claimed that CNN handed him a scripted question to read at its Wednesday town hall broadcast, while another, from CNN, said that charge was untrue.
CNBC saw other posts promoting another storyline that students who heard the shots at first didn't worry about them because they had been prepared for a drill.
After viewing the content for 15 minutes, even a CNBC reporter with more than 20 years of experience in the news business couldn't be sure of many facts about the shooting — except for the deadly reality that 17 lives were cut short in brutal fashion by a teenager with a gun.
The thing that makes Facebook attractive to advertisers is its ability to target messages at individuals that are tailored specifically to their needs, interests and characteristics.
Yet when everyone's news feed is personalized with an avalanche of competing and often contradictory sources, presenting a reality that is not fake, as Facebook hopes to do, could prove impossible.